Field
This disclosure relates to a door lock and more particularly, to a more robust dead-latching slam bolt door lock especially useful for safes and/or lockers placed inside larger safes.
Description of the Related Art
Safes, or high security containers, come in an infinite array of designs. One primary markets is commercial safes, where safes are often designed and manufactured to the client's requirements. Many of these safes are equipped with a conventional outer safe door, but also have locker(s) inside to facilitate different cash handling methods and processes. Electronic safe locks have evolved rapidly to replace mechanical systems since their introduction in the early 1990s.
There are two fundamental locking systems used in safes:
a. Boltwork Blocking: where a safe door is held closed by robust locking bolts, carried by a common carriage bar. The locking bolts are engaged behind a stationary jamb in the safe body. The boltwork is held in the locked position by a safe lock that prevents the articulation of the common carriage bar. These locks are typically “dead-latching,” meaning they can only be disengaged by the actuating the manual or electronic switch to open the lock. The carriage bar is articulated manually by a rotating or sliding handle mechanism.
b. Direct Locking: where a safe lock directly engages the stationary jamb in the safe body. The locks of this type typically include a spring-biased ramped locking bolt that is depressed as the bolt contacts and passes the stationary jamb, thus making it unnecessary to activate the lock to close the locker door. The bolt action of this type of lock would be similar to a conventional door knob-lock, except the retraction is effected by the electronic locking system controls. These locks are often referred to as “Slam Bolt Locks,” as the closing action causes the spring-biased bolt to push open, then spring back behind the jamb when the door is fully closed. The name signifies that you “Slam” the door to close and lock it without any need for lock articulation.
One problem with existing direct locking slam bolt-type locks is that the contents of a safe may interfere with opening of the lock. That is, a weight applied from inside the safe on the door tends to apply an outward load. The spring-biased bolt is thus pressed outward against the door jamb, which might interfere with its smooth opening. The resulting wear imposed on surfaces that were not intended to be structurally loaded may eventually lead to failure. Further, since the bolt must be free to push in as it contacts the jamb during door closure, it likewise can be pressed in against the spring force when the door is closed, and cannot be dead-latched. This is true for solenoid or knob actuated slam bolt locks and presents a security risk, as opening can be accomplished by using a fishing probe from any opening where access may be made. This is also in contrast to a dead-latching lock which can only be disengaged by actuating the manual or electronic switch to open the lock.
There is thus a need for a more robust dead-latching slam bolt lock.